History:

This lady presented with a painful edematous papulovesicular skin lesion at the knee region that within 3 days evolved into a punched-out ulcer with necrotic center and surrounded by an erythematous zone. The ulcer persisted for more than 3 weeks with little tendency for healing.

The commonest types of spiders that sting human are the black widow spider (Latrodectism) which usually produces a generalized and even systemic reactions and the small brown recluse spider (Loxoscelism) which usually causes a localized necrotic cutaneous reaction as in the presented case.